package com.jimi.framework.logger.helper;

import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Map;

// contributors: lizongbo: proposed special treatment of array parameter values
// J�rn Huxhorn: pointed out double[] omission, suggested deep array copy
/**
 * Formats messages according to very simple substitution rules. Substitutions
 * can be made 1, 2 or more arguments.
 * 
 * <p>
 * For example,
 * 
 * <pre>
 * MessageFormatter.format(&quot;Hi {}.&quot;, &quot;there&quot;)
 * </pre>
 * 
 * will return the string "Hi there.".
 * <p>
 * The {} pair is called the <em>formatting anchor</em>. It serves to designate
 * the location where arguments need to be substituted within the message
 * pattern.
 * <p>
 * In case your message contains the '{' or the '}' character, you do not have
 * to do anything special unless the '}' character immediately follows '{'. For
 * example,
 * 
 * <pre>
 * MessageFormatter.format(&quot;Set {1,2,3} is not equal to {}.&quot;, &quot;1,2&quot;);
 * </pre>
 * 
 * will return the string "Set {1,2,3} is not equal to 1,2.".
 * 
 * <p>
 * If for whatever reason you need to place the string "{}" in the message
 * without its <em>formatting anchor</em> meaning, then you need to escape the
 * '{' character with '\', that is the backslash character. Only the '{'
 * character should be escaped. There is no need to escape the '}' character.
 * For example,
 * 
 * <pre>
 * MessageFormatter.format(&quot;Set \\{} is not equal to {}.&quot;, &quot;1,2&quot;);
 * </pre>
 * 
 * will return the string "Set {} is not equal to 1,2.".
 * 
 * <p>
 * The escaping behavior just described can be overridden by escaping the escape
 * character '\'. Calling
 * 
 * <pre>
 * MessageFormatter.format(&quot;File name is C:\\\\{}.&quot;, &quot;file.zip&quot;);
 * </pre>
 * 
 * will return the string "File name is C:\file.zip".
 * 
 * <p>
 * The formatting conventions are different than those of {@link MessageFormat}
 * which ships with the Java platform. This is justified by the fact that
 * SLF4J's implementation is 10 times faster than that of {@link MessageFormat}.
 * This local performance difference is both measurable and significant in the
 * larger context of the complete logging processing chain.
 * 
 * <p>
 * See also {@link #format(String, Object)},
 * {@link #format(String, Object, Object)} and
 * {@link #arrayFormat(String, Object[])} methods for more details.
 * 
 * @author Ceki G&uuml;lc&uuml;
 * @author Joern Huxhorn
 */
final public class MessageFormatter {
	static final char DELIM_START = '{';
	static final char DELIM_STOP = '}';
	static final String DELIM_STR = "{}";
	private static final char ESCAPE_CHAR = '\\';

	/**
	 * Performs single argument substitution for the 'messagePattern' passed as
	 * parameter.
	 * <p>
	 * For example,
	 * 
	 * <pre>
	 * MessageFormatter.format(&quot;Hi {}.&quot;, &quot;there&quot;);
	 * </pre>
	 * 
	 * will return the string "Hi there.".
	 * <p>
	 * 
	 * @param messagePattern
	 *            The message pattern which will be parsed and formatted
	 * @param argument
	 *            The argument to be substituted in place of the formatting
	 *            anchor
	 * @return The formatted message
	 */
	final public static FormattingTuple format(String messagePattern, Object arg) {
		return arrayFormat(messagePattern, new Object[] { arg });
	}

	/**
	 * 
	 * Performs a two argument substitution for the 'messagePattern' passed as
	 * parameter.
	 * <p>
	 * For example,
	 * 
	 * <pre>
	 * MessageFormatter.format(&quot;Hi {}. My name is {}.&quot;, &quot;Alice&quot;, &quot;Bob&quot;);
	 * </pre>
	 * 
	 * will return the string "Hi Alice. My name is Bob.".
	 * 
	 * @param messagePattern
	 *            The message pattern which will be parsed and formatted
	 * @param arg1
	 *            The argument to be substituted in place of the first
	 *            formatting anchor
	 * @param arg2
	 *            The argument to be substituted in place of the second
	 *            formatting anchor
	 * @return The formatted message
	 */
	final public static FormattingTuple format(final String messagePattern,
			Object arg1, Object arg2) {
		return arrayFormat(messagePattern, new Object[] { arg1, arg2 });
	}

	static final Throwable getThrowableCandidate(Object[] argArray) {
		if (argArray == null || argArray.length == 0) {
			return null;
		}

		final Object lastEntry = argArray[argArray.length - 1];
		if (lastEntry instanceof Throwable) {
			return (Throwable) lastEntry;
		}
		return null;
	}

	/**
	 * Same principle as the {@link #format(String, Object)} and
	 * {@link #format(String, Object, Object)} methods except that any number of
	 * arguments can be passed in an array.
	 * 
	 * @param messagePattern
	 *            The message pattern which will be parsed and formatted
	 * @param argArray
	 *            An array of arguments to be substituted in place of formatting
	 *            anchors
	 * @return The formatted message
	 */
	final public static FormattingTuple arrayFormat(
			final String messagePattern, final Object[] argArray) {

		Throwable throwableCandidate = getThrowableCandidate(argArray);

		if (messagePattern == null) {
			return new FormattingTuple(null, argArray, throwableCandidate);
		}

		if (argArray == null) {
			return new FormattingTuple(messagePattern);
		}

		int i = 0;
		int j;
		StringBuffer sbuf = new StringBuffer(messagePattern.length() + 50);

		int L;
		for (L = 0; L < argArray.length; L++) {

			j = messagePattern.indexOf(DELIM_STR, i);

			if (j == -1) {
				// no more variables
				if (i == 0) { // this is a simple string
					return new FormattingTuple(messagePattern, argArray,
							throwableCandidate);
				} else { // add the tail string which contains no variables and
							// return
					// the result.
					sbuf.append(messagePattern.substring(i,
							messagePattern.length()));
					return new FormattingTuple(sbuf.toString(), argArray,
							throwableCandidate);
				}
			} else {
				if (isEscapedDelimeter(messagePattern, j)) {
					if (!isDoubleEscaped(messagePattern, j)) {
						L--; // DELIM_START was escaped, thus should not be
								// incremented
						sbuf.append(messagePattern.substring(i, j - 1));
						sbuf.append(DELIM_START);
						i = j + 1;
					} else {
						// The escape character preceding the delimiter start is
						// itself escaped: "abc x:\\{}"
						// we have to consume one backward slash
						sbuf.append(messagePattern.substring(i, j - 1));
						deeplyAppendParameter(sbuf, argArray[L], new HashMap());
						i = j + 2;
					}
				} else {
					// normal case
					sbuf.append(messagePattern.substring(i, j));
					deeplyAppendParameter(sbuf, argArray[L], new HashMap());
					i = j + 2;
				}
			}
		}
		// append the characters following the last {} pair.
		sbuf.append(messagePattern.substring(i, messagePattern.length()));
		if (L < argArray.length - 1) {
			return new FormattingTuple(sbuf.toString(), argArray,
					throwableCandidate);
		} else {
			return new FormattingTuple(sbuf.toString(), argArray, null);
		}
	}

	final static boolean isEscapedDelimeter(String messagePattern,
			int delimeterStartIndex) {

		if (delimeterStartIndex == 0) {
			return false;
		}
		char potentialEscape = messagePattern.charAt(delimeterStartIndex - 1);
		if (potentialEscape == ESCAPE_CHAR) {
			return true;
		} else {
			return false;
		}
	}

	final static boolean isDoubleEscaped(String messagePattern,
			int delimeterStartIndex) {
		if (delimeterStartIndex >= 2
				&& messagePattern.charAt(delimeterStartIndex - 2) == ESCAPE_CHAR) {
			return true;
		} else {
			return false;
		}
	}

	// special treatment of array values was suggested by 'lizongbo'
	private static void deeplyAppendParameter(StringBuffer sbuf, Object o,
			Map seenMap) {
		if (o == null) {
			sbuf.append("null");
			return;
		}
		if (!o.getClass().isArray()) {
			safeObjectAppend(sbuf, o);
		} else {
			// check for primitive array types because they
			// unfortunately cannot be cast to Object[]
			if (o instanceof boolean[]) {
				booleanArrayAppend(sbuf, (boolean[]) o);
			} else if (o instanceof byte[]) {
				byteArrayAppend(sbuf, (byte[]) o);
			} else if (o instanceof char[]) {
				charArrayAppend(sbuf, (char[]) o);
			} else if (o instanceof short[]) {
				shortArrayAppend(sbuf, (short[]) o);
			} else if (o instanceof int[]) {
				intArrayAppend(sbuf, (int[]) o);
			} else if (o instanceof long[]) {
				longArrayAppend(sbuf, (long[]) o);
			} else if (o instanceof float[]) {
				floatArrayAppend(sbuf, (float[]) o);
			} else if (o instanceof double[]) {
				doubleArrayAppend(sbuf, (double[]) o);
			} else {
				objectArrayAppend(sbuf, (Object[]) o, seenMap);
			}
		}
	}

	private static void safeObjectAppend(StringBuffer sbuf, Object o) {
		try {
			String oAsString = o.toString();
			sbuf.append(oAsString);
		} catch (Throwable t) {
			System.err
					.println("SLF4J: Failed toString() invocation on an object of type ["
							+ o.getClass().getName() + "]");
			t.printStackTrace();
			sbuf.append("[FAILED toString()]");
		}

	}

	private static void objectArrayAppend(StringBuffer sbuf, Object[] a,
			Map seenMap) {
		sbuf.append('[');
		if (!seenMap.containsKey(a)) {
			seenMap.put(a, null);
			final int len = a.length;
			for (int i = 0; i < len; i++) {
				deeplyAppendParameter(sbuf, a[i], seenMap);
				if (i != len - 1)
					sbuf.append(", ");
			}
			// allow repeats in siblings
			seenMap.remove(a);
		} else {
			sbuf.append("...");
		}
		sbuf.append(']');
	}

	private static void booleanArrayAppend(StringBuffer sbuf, boolean[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void byteArrayAppend(StringBuffer sbuf, byte[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void charArrayAppend(StringBuffer sbuf, char[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void shortArrayAppend(StringBuffer sbuf, short[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void intArrayAppend(StringBuffer sbuf, int[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void longArrayAppend(StringBuffer sbuf, long[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void floatArrayAppend(StringBuffer sbuf, float[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}

	private static void doubleArrayAppend(StringBuffer sbuf, double[] a) {
		sbuf.append('[');
		final int len = a.length;
		for (int i = 0; i < len; i++) {
			sbuf.append(a[i]);
			if (i != len - 1)
				sbuf.append(", ");
		}
		sbuf.append(']');
	}
}